Hydrocarbon tin selenides and tellurides and process for their preparation



United States Patent HYDROCARBON TIN SELENIDES AND TELLU- lllllggs AND PROCESS FOR THEIR PREPARA- Elliott L. Weinberg, Long Island City, N. Y., and Louis A. Tomka, Westfield, N. 1., assignors to Metal &

Thermit Corporation, New York, N. Y., a corporation of New Jersey 9 Claims. (Cl. 260-429.7)

The present invention relates to the stabilization of elastomers against the deleterious effects of aging, and especially the stabilization of rubbery compositions of the class consisting of natural rubber and synthetic polymers. Elongation, tensile strength, modulus, tackiness, etc., as well as other properties of elastomers are adversely affected by aging in the absence of stabilizers normally termed rubber anti-oxidants.

We have discovered that an organotin compound having the structural formula 2 QJn is an effective anti-oxidant for natural and synthetic rubber compounds.

In the above formula R is a hydrocarbon group, Q is a group VIb element in the periodic table of the elements, and n is an integer. n may be 1 indicating a monomeric product or it may be greater indicating a polymer. When Q is sulfur there is reason to believe that n is usually 3, that is, that the product is a cyclic trimer. R may be more specifically defined as a univalent organic radical, such as an alkyl, aralkyl or aryl radical, including methyl, ethyl, butyl, propyl, lauryl, tolyl, phenyl, phenylethyl, diphenyl or benzyl; it is not necessary that each R group be identical. Q, more specifically, is selected from the group consisting of sulfur, selenium and tellurium except that in polymeric compounds oxygen may replace some sulfur atoms to produce oxysulfides such as for example R2511 SnR; R284 snRz or s Sn Sn R2 R2 The hydrocarbontin sulfides are conveniently made by passing hydrogen sulfide through a suspension of hydrocarbontin oxides in an inert solvent such as toluene. When not enough hydrogen sulfide is passed there is produced a mixture of oxysulfide species. This mixture may be used without separation as an eifective rubber stabilizer or antioxidant.

The hydrocarbontin selenides and tellurides may be made by the reaction of a hydrocarbontin halide with alkali metal selenide or telluride. For instance dimethyltin selenide may be prepared by dissolving 22 grams (0.1 mole) of dimethyltin dichloride in 50 ml. water and mixing with a solution of 12.5 grams (0.1 mole) of sodium selenide in 150 ml. air free water. The resulting mixture may then be filtered and the resulting white precipitate washed and dried in a vacuum oven. For hydrocarbontin chlorides other than methyl, the chlorides would be dissolved in ethanol instead of water.

Dibutyltin telluride may be made by passing hydrogen telluride, generated by the action of dilute hydrochloric acid on aluminum telluride, into a slurry of dibutyltin 2,858,325, Patented Oct. 28, 1958 oxide in toluene, until substantially all of the dibutyltin.

oxide is consumed. The solution may then be heated to expel excess hydrogen telluride. The solvent may then be distilled off, in vacuo, together with the water formed by the reaction, leaving a residue of solid dibutyltin telluride. 1

Compounds of the above type have been demonstrated to be extremely effective; Their effectiveness is illustrated by their stabilizing ability at exceptionally low concentrations and are effective at .05 to 5% based on the weight of the rubber with a preferred range of .1 to 1% stabilizer based on the weight of the rubber.

These stabilizers are non-staining, and do not cause discoloration of rubber stocks as' other anti-oxidants commonly do. This permits the manufacture of stable White stocks.

The stabilizers disclosed herein can be effectively used as anti-oxidants with elastomers and specifically with rubbery materials of the class consisting of (a) natural rubber, (b) rubber-like copolymers of 1,3 butadiene and styrene (GR-S type), (c) rubber-like copolymers of 1,3

butadiene and acrylonitrile (nitrile type) and (d) rubber-like homopolymers of chloroprene (neoprene type).-

The organotin compounds may be milled into the rubbery materials defined above, Without other additions,-

for the purpose of preventing degradation during storage. More commonly they will be incorporated with other materials during compounding.

Any suitable compounding formulation may be employed. A specific example of a natural rubber composition, in which the organotin derivatives described is effective as an anti-oxidant is as follows:

To this composition may be added any of the organotin compounds coming under the general formula set forth above, in the proportions of 0.05% to 5% by weight, based on the Weight of the rubber ingredient of said composition and preferably in the approximate 0.1% level. This compounded rubber composition containing the stabilizer is Worked and blended by conventional techniques and vulcanized at 275 F. for twenty minutes in an hydraulic press.

The effectiveness of the organotin compound described as an anti-oxidant is indicated by the following test results carried out with the specific rubber composition described above containing anti-oxidant in the amounts and manner shown below.

The test methods employed to determine the anti-oxidant properties consisted of 1) outdoor exposure and (2) the Oxygen Bomb TestASTM Procedure D-572- 48. The outdoor exposure test samples were examined for tackiness, surface checking and discoloration. The

oxygen bomb test samples were examined for changes in tensile strength, elongation and modulus by means of standard equipment.

Sample Color Tackiness Surface Checking EX. 1 No discoloration Pronounced. Pronounced.

. (1 Very slight.

Do. Do. Do. Do. do D0.

Discolored Pronounced.

Oxygen Bomb Test-4 days 70 C.

"Modulus (p. s. i.) Percent .(p.-s. i.) 200% Tensile Elongation Sample Elongation Strength Orig. Aged Orig. Aged Orig. Aged Similar tests on GR-S rubber (1,3-butadiene-styrene) indicatethat the stabilization of synthetic rubber with organotin compounds of the general type described, is just'as'pronoun'ced as it is inthe'case of natural rubber.

Although the examples show the stabilizer used with natural rubber crepe and with-coagulated GR-S (1,3 butadiene and sytrene), incorporation of the stabilizer into latices is possible. The latices Would then be processed in the usual manner.

The rubbercomposition to be stabilized may contain quantities of pigments to impart any desired color or decorative eflect to the final product. The stabilizer will cause the rubber composition to maintain its color whether it is black, white or any'other color.

Whilethe invention has been described with reference to various'samples and embodiments, it will be apparent to those skilled in' the art that various modifications may 4 bernade, 'and'e'quivalents' substituted therefor, without'departing from the principles and true nature of the invention.

What is claimed is:

1. A hydrocarbontin compound of formula R SnQ wherein R is a hydrocarbon radical selected from the class consisting of alky, aryl and aralkyl radicals and Q is selected from the class consisting of selenium and tellurium.

2. A compound according to claim 1 wherein R is alkyl and Q is selenium.

3. A compound according to claim 1 wherein R is alkyl and Q is tellurium.

4. A process for preparing a hydrocarbontinselenide of formula R SnSe which comprises reacting a hydrocarbontin halide of formula R S nX with an alkali metal I selenide, wherein R is a hydrocarbon radical selected from the class consisting of alkyl, aryl and aralkyl radical, and X is halogen.

5. A process according to claim 4 wherein R is alkyl and X is chlorine.

6. A process for preparing a hydrocarbontin compound of formula RSnTe which comprises reacting a hy drocarbontin halide of'formula R SnX with an alkali metal telluride, wherein R is a hydrocarbon radical selected from the class consisting of alkyl, aryl and aralkyl radicals and X is halogen.

7. A'process according to claim 6 wherein 'R is alkyl and X is chlorine.

8. A process for the preparation of a hydrocarbontin selenide of formula R SnSe which comprises reacting a hydrocarbontin oxide of formulaR snO with hydrogen selenide, wherein R is a hydrocarbon radical selected from the class consisting of alkyl, aryl and aralkyl radicals.

9. A process according-to clairn8-wherein-R is alkyl.

Carroll May 27, 1952 Johnson Sept. 18, 1956 

1. A HYDROCARBONTIN COMPOUND OF FORMULA R2SNQ WHEREIN R IS A HYDROCARBON RADICAL SELECTED FROM THE CLASS CONSISTING OF ALKY, ARYL AND ARALKYL RADICALS AND Q IS SELECTED FROM THE CLASS CONSISTING OF SELENIUM AND TELLURIUM. 